1. Field of the Invention
This invention relates to copolymers of 1,2-dimethoxyethylene with .beta.-lactones of cyclic six-membered ring carbonates. More particularly, this invention relates to water insoluble copolymers of 1,2-dimethoxy ethylene and .beta.-lactones or cyclic six-membered ring carbonates and to a process for their production. This invention is also directed to the use of the resultant copolymers as a fusion adhesive. Another possible application is in the field of elasticizing agents, e.g. for plastics.
2. Discussion of the Prior Art
In co-pending application, Ser. No. 207,648 now U.S. Pat. No. 3,792,030 of Feb. 12, 1974 there is disclosed the preparation of homopolymers of 1,2-dimethoxyethylene (DMOE) by contacting 1,2-dimethoxyethylene at a temperature in the range of 0.degree. to -80.degree.C with an initiator which is a halogen-containing organoaluminum compound such as diethyl aluminum chloride. Homopolymers of 1,2-dimethoxyethylene which are water-soluble are prepared. These polymers have an osmotic average number molecular weight between about 60,000 and 350,000. A portion of the polymer has a crystalline structure.
It has become desirable to prepare copolymers of DMOE with other organic residues. However, difficulties have been encountered in the preparation of such copolymers. For instance, in one of the earlier cases wherein 1,2-dimethoxyethylene was employed in a copolymerization pure poly-DMOE was obtained. Thus, when it was attempted to polymerize dimethoxyethylene with isobutylene, methylmethacrylate and butadiene, pure poly-DMOE was obtained (see U.S. Pat. No. 2,526,743). The reason for this probably lies in the fact that dialkoxyethylenes, especially dimethoxyethylene are characterized by a violent homopolymerization, especially when Lewis acids are utilized.
Attempts have also been made to form copolymers of monomers which polymerize by undergoing a ring opening with monomers which polymerize with the elimination of an olefinic double bond. One of the first cases of this type of copolymerization involves an attempt to copolymerize trioxane with styrene. Attempts have been made also to prepare copolymers of .beta.-propiolactone and acrylic acid, as well as vinyl compounds. Thus, Okamura et al obtained, in the irradiation of a monomer mixture of .beta.-propiolactone and the vinyl related compound, acrylonitrile, with gamma rays, an insoluble copolymer. See Journal of Polymer Science, Vol. 58, page 925 (1962). Katayama et al succeeded in triggering, with sodium cyanide as the initiator, an anionic copolymerization between .beta.-propiolactone and acrylonitrile. (Journal of Polymer Science A-1, Polymer Chemistry 9 (1971) No. 5, p. 1173).
The cationic polymerization of lactones was said to be especially difficult with monomers exhibiting a very rapid cationic homopolymerization. Thus, attempts have been made for the cationic copolymerization of styrene with .beta.-propiolactone (Ito et al., "Makromolekulare Chem." [Macromolecular Chemistry] 117 (1968), 279). However, with the aid of the initiators employed, especially borontrifluoride etherate, essentially mixtures of the two homopolymers were produced.
Considering the fact that the preparation of copolymers with .beta.-propiolactones and monomers which were characterized by a very rapid cationic homopolymerization was extremely difficult yielding inevitably a mixture of homopolymers, it was considered that the copolymerization of DMOE with .beta.-propiolactone or pivalolactone would fail. This is reinforced by the fact that attempts to polymerize DMOE with isobutylene, methylmethacrylate and butadiene also failed. Additionally, attempts to polymerize DMOE with .beta.-propiolactone or pivalolactone in the presence of Lewis acids, such as borontrifluoride etherate or tintetrachloride resulted in pure DMOE only.
It, therefore, became desirable to provide a means by which DMOE could be copolymerized with .beta.-lactone. It became desirable to provide a water insoluble copolymer of DMOE since homopolymers of DMOE are water-soluble in the osmotic average number molecular weight range of between about 60,000 and 350,000.